Rewrite app: entries → projects with S3 file storage

Replace flat text entries with project-based structure.
Each project has name, local/corp fields, content textarea,
and file upload (up to 100MB) stored in MinIO S3.
New API: CRUD projects + file download + content copy.
Frontend: two views (project list + project page).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/nginx.conf

@@ -1,6 +1,7 @@
 server {
     listen 80;
     server_name _;
+    client_max_body_size 110m;
 
     location / {
         root /usr/share/nginx/html;
@@ -13,5 +14,6 @@ server {
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_read_timeout 300s;
     }
 }